Muscle Notes

Things That Aren’t Muscles… Tendons, ligaments, and cartilage…

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Muscle Notes

Things That Aren’t Muscles…Tendons, ligaments, and cartilage…

What holds your joints together and keeps them connected as you move?Bones come

together at joints and are held together by ligaments.

Cartilage, a soft type of protein, acts as padding and helps to decrease friction when bones must rub together.

Arthritis is a disease you get when your cartilage wears down. It hurts!

TendonsPart of a team with

muscles and bones, to move bones.

Tendons: strong connective tissue that attach muscle to bone.

How tendons work: Muscle contracts, pulls tendon, tendon pulls bone

Notice: tendons attach muscles to TWO DIFFERENT bones!

Tendonitis is an injured, enflamed tendon. It hurts!

Another tendon attaches this end of the muscle to bone.

LigamentsProvide joint stability and

flexibility.strong connective tissue

bands, connect bones around a joint.

“Elastic” to allow the movement of joint, strong enough to stop movement outside the normal range.

Example: keeps knee in line, hips in line, etc.

You may have heard of torn ACLs (anterior cruciate ligament around the knee).

Torn ligaments will make your joints bend the wrong way and look very, very bad.

CartilageCartilage: soft

cushioning protein that covers ends of bones.

A shock absorber and reduces the rubbing of the bone surfaces at joints.

Arthritis: when cartilage wears down to expose bone; bone on bone contact is painful!

Bones help you move –because your muscles are attached to your bones by tendons.

I’ve got to hurry to slow the pace of global warming!

Muscles and Mice? Muscle has Latin roots

meaning “Little Mouse” because it looked like a mouse was running under the skin.

the prefix “Myo” or “Mys” refers to “muscle”.

Muscles help you move, generate most of the body’s heat, and help you maintain your posture.

Turkey Anatomy

Muscles contract (shorten) to bring their ends closer together.

Muscles relax (lengthen) to let their ends move apart.

Muscles can only pull! They can NEVER push!

Important Notice!

Basic muscle functionHow muscles work together in opposing

pairs.one muscle flexes, pulls bones together, as an

opposing muscle will relax; to reverse this, another muscle will extend while the first muscle will relax.

Examples: biceps brachii flexes to pull the forearm up to shoulder, while triceps brachii relaxes

triceps brachii will extend, to pull the forearm away from the shoulder, while biceps brachii will relax

Flexion (flexing)-bending

Flexion - a motion that decreases the angle between two bones, or pulls two bones closer together. An example of an arm flexor is the biceps brachii.

Extension: straightening out

Extension - a motion that increases the angle between two bones, or moves two bones farther apart. An example of an arm extensor is the triceps brachii.

See Animation of flexion of the bicep in upper arm.

Abduction- Away from center Adduction- Toward center

Abduct -Moving a skeletal element from the midline via a muscle.

Adduct -Moving a skeletal element toward the midline.


Supination/Pronation Pronation - rotation

of forearm so the palms face down. (Supination & Pronation can also be found at the ankle.)

Supination - rotation of the forearm so the palms face up.

Muscle Parts

There are more than 600 muscles in the body. Most of them move parts of the body or help it stay upright. Muscles cannot push, they can only pull. Many of them work in pairs, attached to bones by tendons. One muscle tightens and becomes shorter, pulling the bone after it. If it relaxes, and the other muscle tightens, the bone moves back.

How Does a Muscle Work? A muscle contraction happens because two protein filaments (myofiliments named Actin and Myosin) pull on each other and shorten the muscle fiber. One muscle fiber can not do much work, but lots of them can “pull together” to do an amazing amount of work . (It’s kind of analogous to Velcro.)

But where are these secret proteins located in the muscle?

Some key muscle termsSome key terms for muscle structure and

function…Muscle Fasicles

Muscle Fibers, aka muscle cells Myofibrils contain Myofiliments (Actin

and Myosin)

Overview Of Muscle Tissue

Fancy Pants DefinitionsMuscles: A tissue consisting of contractile cells

and proteins which move bone parts, or fluids through organs such as peristalsis in the esophagus.

Fasicle: Bundle of muscle cells grouped together to do work

Muscle Fiber: Muscle cell. These cells are especially adapted to contract when nerves “excite” them to move.

Myofibril: Contains the two types of myofiliments, Actin (thin) and Myosin (thick). These two proteins react with each other to shorten and relax. ATP molecules provide the energy which causes this action to occur.

Muscle Control Skeletal muscle, as its

name implies, is the muscle attached to the skeleton. The contraction of skeletal muscle is under “voluntary” control, so you can choose to move them.

We also have cardiac muscle (in the heart) and smooth muscle (in internal organs, like stomach, intestines, esophagus, lungs, blood vessels). These muscles types are “involuntary” and your brain controls them.

Motor cortex is a term that describes regions of the cerebral cortex involved in the planning, control, and execution of voluntary movements.

13 Muscles to know1. Biceps brachii: flex

lower arm; lift2. Triceps brachii:

extend lower arm; punch

3. Quadriceps: extends lower leg; kick

4. Biceps femoris: flex lower leg; kick

5. Gluteals: lift leg at thigh

6. Gastrocnemius: flex foot; tippy toes,

walk7. Rectus abdominus:

sit-ups8. Trapezius: extend

neck; shrug!9. Deltoids: lift arm to

side10.Pectorals: lift arm to

front11.Masseter and

Temporalis: chew12.Heart: pump blood!